Duplicating machine

ABSTRACT

A machine for automatically making multiple copies of a document on bond paper by first making a copy on zinc oxide paper, transferring toner from the zinc oxide copy onto a master sheet, and using the master sheet as a lithographic master for printing on ordinary paper. The machine utilizes a single transport drum to move the zinc oxide paper past stations where an image is focused thereon and developed, to carry a sheet of master material on top of the zinc oxide copy past an infrared heater for transferring toner from the copy to the master, to carry the master to a printing cylinder around which the master is to be wrapped, and to thereafter carry sheets of bond paper past the master on the printing cylinder.

United States Patent Kaminstein et al.

15 3,682,095 1 Aug. 8, 1972 [54] DUPLICATING MACHINE [72] Inventors: Bernard Kaminstein, Paramus; Lu-

ciano Rattin, River Edge, both of [21] Appl. No.: 39,772

' [52] US. Cl. ..101/463, 101/141, 101/450 [51] Int. Cl. ..B4lm 5/00 [58] Field of.Search ..101/463, 467, 470, 471, 141,

[56] References Cited UNITED'STATES PATENTS 3,426,678 2/ 1969 Carper et al. 101/450 X 3,350,202 10/1967 Silver ..10l/463 UX 3,491,684 1/ 1970 Borinsky ..1 0l/463 X 3,414,724 12/1968 Kvarnegard 101/470 X 3,246,148 4/1966 Troeyer et al. 101/470 X 3,093,068 6/ 1963 Gundlach et al ..l01/463 X 3,088,402 5/1963 Newman ..101/471 3,390,634 7/1968 Verderber ..101/463 3,203,344 8/1965 Newman ..101/471 3,451,336 6/1969 Mignone 101/450 X 3,364,857 l/1968 Lein et al ..l0l/467 X 3,107,169 10/1963 Bornarth ..96/1 2,954,291 9/1960 Clark ..96/1 3,257,942 6/ 1966 Ritzerfeld et al. 101/ 149.4

Primary Examiner-Robert E. Pulfrey Assistant Examiner-R. T. Rader Attorney-Kevin McMahon and Samuel Lindenberg [57] ABSTRACT A machine for automatically making multiple copies of a document on bond paper by first making a copy on zinc oxide paper, transferring toner from the zinc oxide copy onto a master sheet, and using the master sheet as a lithographic master for printing on ordinary paper. The machine utilizes a single transport drum to move the zinc oxide paper past stations where an image is focused thereon and developed, to carry a sheet of master material on top of the zinc oxide copy past an infrared heater for transferring toner from the copy to the master, to carry the master to a printing cylinder around which the master is to be wrapped, and to thereafter carry sheets of bond paper past the master on the printing cylinder.

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PosuTuom SEIQSQQ Z l q? Bee J2me KpM/MsTE/U Lac/ado .g-flTT/U INVENTORS BY M QTTOQJEYS 1 DUPLICATING MACHINE BACKGROUND OF THE INVENTION I. Field of the Invention:

This invention'relates to apparatus for copying or duplicating documents and the like.

2. Description of the Prior Art: 7

One method of making copies of documents on ordinary bond paper involves the production of a preliminary copy on zinc oxide paper, such preliminary copy containing toner particles that form the image. A sheet of transparent plastic material is laid on the preliminary copy, and infrared radiation is applied through it to heat the toner particles of the preliminary copy and cause them to stick to the transparent sheet. The transparent sheet with toner particles sticking thereto and zinc oxide held to the toner particles, is stripped from the zinc oxide preliminary copy and mounted. on the printing drum of a lithograph machine. The lithograph machine is then operated to make copies on ordinary bond paper, the transparent sheet serving as the printing plate or master. This method is described in US. Patent Application Ser. No. 807,325, filed March 14, 1969 by Bernard Kaminstein, entitled, INKING SYSTEM FOR PRINTING, and assigned to the same assignee as the present application.

This process for making copies can be performed by utilizing an ordinary copying machine that makes zinc oxide or other copies, a special transfer machine for transferring the toner image from a preliminary copy to a master sheet, and a lithograph machine for using the master sheet to print many copies on ordinary bond paper. However, such a combination of machines would require an operator to perform many intermediate steps, and this would reduce its acceptance in business offices for making copies. Another approach would be to combine the three machines by utilizing one large cabinet mounting an ordinary copying machine at one end of the cabinet, an image transferring machine in the middle of the cabinet, and a lithograph duplicating machine at the opposite end of the cabinet. In addition, automatic sheet-handling devices would have to be employed to carry the preliminary copy to the transfer device, and to strip and carry the master from the transfer device to the lithograph machine and mount it on the printing drum thereon.

The combination of all of these devices in series would result in a complex and expensive machine which would greatly limit its acceptability.

OBJECTS AND SUMMARY OF THE INVENTION An object of the present invention is toprovide a compact and simple machine for making duplicates of.

a document.

Another object is to provide an economical machine for automatically producing multiple copies of a docube printedupon. The use of a single transport drum for moving the three kinds of sheets involved in the duplicating process, results in considerable simplifica-- tion and reduction in size.

Various stations for use during a complete cycle of the machine are spaced about the transport drum. These include an imaging station-for focusing an image onto a sheet of zinc oxide paper that is carried on the drum, and a developing station for developing the image by applying toner particles to the zinc oxide paper. A heating station positioned adjacent to the transport drum applies heat through a transparent master sheet that has been laid on the preliminary copy as it is moved by the transport drum. The heat fuses the toner to the master sheet. A printing drum is positioned adjacent to the transport drum to pick up the transparent master after is has been fused to toner on the preliminary copy and to zinc oxide particles that are held to the toner, so that the master is immediately mounted on the printing drum. The location of the printing drum adjacent to the transport drum allows the transport drum to thereafter serve as a roller for pressing sheets of bond paper against the master on the printing drum. The sheets of paper are fed onto the transport drum and carried by it across the printing drum where an ink image is printed on the paper, and then to a conveyor that removes the sheets and carries them to a basket.

The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings. 1

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a simplified side-elevation view of a reproducing machine constructed in accordance with the invention;

FIGS. 2A through 2C are partial views of the FIG. 5 is a simplified schematic view of a control system for the reproducing machine of FIG. 1;

FIG. 6 is a partial side elevation view of the transport drum and of a mechanism for operating the gripping lever thereof; and

FIG. 7 is a partial plan view of the apparatus of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. I illustrates a machine which can receive a document D or other material to be reproduced, and make multiple printed copies .of its automatically. The machine operates by first making a preliminary copy by an electrophotographic process, which involves form'- ing an optical image of the document on imagable material, that is, material which can forma continuing image of an optical image focused thereon. A roll 10 of preliminary copy material such as zinc oxide coated paper is utilized, by feeding out and cutting off a sheet from this roll and wrapping the sheet around a transport drum 12. As the drum 12 rotates, an optical image of the document D is focused on the surface of the zinc oxide sheet by optical apparatus 14 defining an imaging station 16. The image on the zinc oxide sheet is developed at a developing station 18 which applies toner particles to image areasof the sheet, thereby creating a preliminary copy containing the image of the document D.

As the preliminary copy rotates on the transport drum 12, a sheet of master material from a roll 20 is fed onto the transport drum 12 over the developed preliminary copy thereon. The master material may be a sheet of transparent flexible material of a type which is softened at relatively low temperatures, such as polystyrene. As the transparent master material is fed over the preliminary copy, infrared radiation from a heating station 22 is projected at the master sheet. The infrared rays pass through the transparent master material and heat the dark regions of the preliminary copy, the dark regions being the regions which have received the black toner particles. The heated toner particles heat the regions of the master sheet which they contact, and cause the toner particles to fuse to the master sheet. As the preliminary copy continues rotating on the transport drum 12, the master sheet or printing master is peeled off the preliminary copy and onto a printing drum 24, toner particles and zinc oxide particles that stick to the toner particles leaving the preliminary copy and holding to the master sheet. The preliminary copy remnant is thereafter peeled off the transport drum and moved by a remnant drive 26 into a remnant basket 28.

The master sheet is wrapped fully about the printing drum 24 so that it can be used as a lithographic master in a reverse lithographic printing process. The master on the printing drum 24 is first prepared by applying a special oil to its surface by an oil injector device 30. A mixture of ink and oil is then applied to the surface of the master sheet by an ink cartridge 32. Ordinary bond paper from a paper holder 34 is then fed along a belt 36, around a pick-up roll 38, and onto the transport drum 12. The transport drum moves the sheets of paper past the inked master'sheet on the printing drum 24, and onto an output belt 40 which carries the printed sheets to a copies basket 42.

After the desired number of printed copies have been made, the master sheet on the printing drum 24 is stripped off and made to pass into the remnant drive 26 and thereafter into the remnant basket 28. The machine is then ready to receive a new document and make printed copies of it. The apparatus is constructed so that it functions automatically, a human operator being required only to position the document D on the machine, maintain supplies of the various sheet materials, oil and ink, and take away the printed copies and remnants. If a large number of copies of one document 7 2A, the apparatus first separates a sheet 10' of the zinc oxide preliminary copy material and moves it onto the transport drum 12. This is accomplished by rotating a pair of rollers 44, 46 to feed out the material from the supply roll past a knife 48. After a sufficient length of the zinc oxide paper has been fed out, the knife 48 is operated to cut the sheet, and the rollers 44, 46 are stopped. The sheet 10' passes through another set of rollers 50, 52 that move it through an electrostatic charging station 54 where an electrostatic charge is applied to the sheet. The sheet is then carried onto the transport drum 12, and its leading edge 10L is gripped to the drum.

As the zinc oxide sheet 10 moves with the transport drum 12, all portions of the sheet move past the imaging station 16 where the document D is imaged. The optical system 14 for focusing the image on the zinc oxide paper includes a glass plate 56 upon which the document is placed, a set of three mirrors 58, 60 and 62 for reflecting light from the document towards the transport drum 12, and a lens 64 for focusing the image substantiallyat the surface of the drum, and therefore on the zinc oxide paper wrapped thereon. As the transport drum 12 slowly rotates, the lens 64 remains stationary, but the mirrors move to scan the document. Mirrors 58 and 60 are mounted on a first carriage that passes completely along the document, while the mirror 62 is mounted on a second carriage that moves parallel to the first but at one-half the speed. This optical system is described in U.S. Pat. application Ser. No. 31,713, filed Apr. 24, 1970 by Post et a1, entitled, OP- TICAL DRIVE SYSTEM FOR REPRODUCING MACHINE and assigned to the same assignee as the present invention.

The image focused on the zinc oxide sheet 10' causes dark areas of the image to retain their electrostatic charge while dissipating the charge at the bright image areas. The sheet then passes by the developer station 18 where a roll type brush 66 applies toner particles to the sheet. The toner particles adhere only to charged regions of the sheet, and therefore develop the optical image previously focused on the sheet. Thus, the apparatus automatically produces a preliminary copy by electrophotographic methods at the transport drum 12. Referring to FIG. 2B, the cycle continues by feeding out material from the master supply roll 20 utilizing a pair of feed rollers 68, 70. The master material passes through a knife 72 which severs the sheet after a sufficient length has passed therethrough to form a master sheet 20'. The master sheet is fed onto the transport drum 12 at the same position where the zinc oxide sheet was originally fed onto the drum. The master sheet is laid over the preliminary copy 10' already on the transport drum, with the leading edge of the master sheet positioned slightly ahead of the zinc oxide preliminary copy. Apparatus at the heating station 22 is the activated.

The heating apparatus 22 includes an infrared lamp 74 which is surrounded by a transparent roller 76. The apparatus is activated by turning on the infrared lamp and moving the transparent roller 76 against the master sheet to press it against the preliminary copy on the transport drum. As infrared radiation is directed at the master sheet, it passes through the transparent master sheet to the surface of the preliminary copy. The darkened areas of the preliminary copy absorb the heat and therefore these areas heat regions of the master material which they contact. The master material melts at these regions to an extent wherein it becomes tacky and grips, or fuses to the toner particles of the preliminary copy. The toner particles, in turn, grip zinc oxide particles under them.

As the transport drum rotates, the leading edge 20L of the master sheet reaches the nip 78 between the transport drum 12 and printing drum 24. Apparatus on the printing drum 24 then grips the leading edge of the master sheet. As the transport drum l2 and printing drum 24. rotate, while respectively gripping and preliminary copy and master sheet the master sheet is stripped off from the preliminary copy, carrying toner particles and zinc oxide particles of the preliminary copy with it. The preliminary copy 10' is no longer needed, and it is stripped off the transport drum l2 and moved to the remnant basket. A master sheet 20 has therefore been produced which includes a sheet of flexible material with toner and zinc oxide particles thereon corresponding to the image (reversed) on the document.

Referring to FIG. 2C, as the duplicating cycle proceeds, the master sheet20 becomes fully wrapped about the printing drum 24, and its trailing edge 20T is gripped thereon. The apparatus is then ready to utilize the master sheet 20' as a lithographic master to print copies of the document. Prior to actual printing, the surface of the master sheet is treated with oil and ink from a preoiling and inking device which has a roller 80 that applies a small quantity of oil and ink to the surface of the master sheet. The roller 80 coats the entire master with a uniform coating of the oil, which is a hydrophobic liquid (rejects water and water-based inks). The oil which is deposited on the background plastic (polystyrene) areas remains on the surface and prevents that portion of the surface from being wetted subsequently by ink. The portion of the oil deposited on the zinc oxide image areas is absorbed by the zinc oxide, leaving the rough surface of the zinc oxide relatively free of oil and able to accept ink which is applied subsequently. Ink is applied to the master by use of the ink cartridge 32 which is filled with water-based ink. After oil has been applied to the master sheet, form rolls 82 of the ink cartridge are lowered against the master sheet to apply ink to the image areas of its surface. An ink cartridge suitable for this purpose is described in US. Pat. Application Ser. No. 826,623, filed May 21, 1969, by Hamilton and assigned to a common assignee.

The production of printed copies is accomplished by feeding sheets of paper from the paper holder 34 across the ink-wetted master on the printing drum 24. Suction feet or other well known devices can be used to lift individual sheets from the stack in the basket 34 and place them on the belt 36. The sheets are thereafter picked up by the pick-up roll 38 and fed onto the transport drum 12. The transport drum carries the sheets through the nip 78 between itself and the printing drum 24, so that the sheets of paper are pressed against the master sheet to receive ink therefrom. The sheets of paper are then fed onto the output belt 40 where they are carried to the copies basket. Thus, the transport drum 12 is again utilized, this time to carry sheets of bond paper to be printed upon by the master sheet.

The transport drum 12 is generally rotated slowly during the production of the preliminary copy and the transfer of the image therefrom to the master sheet. However, during the printing drums can be rotated more rapidly to quickly print the required number of copies from the master sheet. As mentioned above, after printing of the required number of copies, the master sheet is stripped from the printing drum and carried to the remnant basket so that the machine is clear for a new reproducing cycle.

FIG. 3 illustrates some of the details of the various stations and devices around the transport drum 12, that feed sheets onto or remove sheets therefrom and which treat sheets moving along the drum. The transfer drum has a smooth surface except at one sector which has mechanisms for gripping sheets. A gripping lever 94 pivotally mounted about a shaft 96 on the drum has fingers 98 that can hold down a sheet of material. A blanket 92 of material such as Teflon extends around the smooth region of the drum to provide a smooth surface that receives sheets of material, and to help in ink transfer from the master to the copy paper. The Teflon blanket is also advantageous because it rejects ink and eliminates the need for cleanup, in case of paper misfeeding when the master presses directly on the blanket, and because it can be readily replaced if it is scratched.

At, the beginning of a duplicating cycle, as the leading edge of a sheet of zinc oxide preliminary material approaches the transport drum 12, the drum is stationary. At this time, the gripping lever. is held in a position wherein the fingers 98 thereon are away from the drum to allow the leading edge of the zinc oxide paper to be received under them. When the leading edge of the zinc oxide paper passes under the fingers 98, the gripping lever 94 is pivoted to allow the fingers to firmly grip the sheet. At this time, the transport drum l2 begins rotating in the direction of arrow 100 at a slow speed such as 2 inches per second. As soon as the transport drum has moved the leading edge of the preliminary copy sheet to the scanning station 16, the optical scanning of the document begins, by movement of the mirror-holding carriages described earlier. The transport drum continues to rotate at a constant speed so that all portions of the preliminary copy material pass by the scanning station.

As the transport drum continues to rotate, it brings the preliminary copy material past the roll 66 of the developing station. The developing station includes a pan 102 having a region 104 filled with iron powder, and toner. The toner coats the iron powder particles, and the toner constitutes about 50 percent of the weight of the mixture and therefore most of the volume. A feeding roller 106 with a magnet along one portion of its periphery, feeds a supply of toner-coated iron powder past a doctor blade 107 into another region 108 within the pan. The roll 66 has a permanent magnet 1 10 within it which attracts the coated iron particles to itself. As the roll 66 rotates against the preliminary copymaterial on the transport drum, it brings or brushes the toner-coated iron particles against the preliminary copy sheet. The iron particles stick to the charged regions of the sheet, thereby developing the image into a dark area on the lighter background of the sheet. The transport drum l2 continues to rotate to bring the leading edge of the preliminary copy back to its starting point where it was fed onto the drum. As the transport drum has been moving the preliminary copy sheet in its first revolution on the drum, a transparent master sheet begins to be fed along its path to the drum. The master sheet is fed so that its leading edge reaches the end of sheet guides 112 and moves onto the transport drum just ahead of the leading edge of the preliminary copy. Accordingly, the leading edge of the'master sheet overlaps the preliminary copy by a short distance such as -1 inch. As soon as the leading edge of the master sheet has been fed onto the transport drum, the infrared heating mechanism 22 is activated.

The transparent roller 76 of the heating mechanism is rotatably mounted between a pair of outer rollers 114, 116 and an inner roller 118. The infrared lamp 74 is mounted within the transparent roller 74 is mounted within the transparent roller 76, and within a reflector 120 that concentrates the lamp rays. The rollers 114, 116 and 118 as well as the lamp and reflector are all mounted on a frame 122 that can be moved a small distance towards and away from .the transport drum 12. As soon as the leading edge of the master sheet has been received on the transport drum, the frame 122 is moved towards the transport drum so that the transparent roller 76 bears against the master sheet. At the same time, the infrared lamp 74 is energized. The force on the transparent roller 76 causes it to press the master sheet firmly against the preliminary copy. At the same time, the radiation from the lamp applies heat that causes the darkened image areas to adhere to the master sheet.

After passing by the infrared heating station, the leading edge of the master sheet moves approximately another one-eighth turn of the transport drum, and it then reaches a region near the nip of the transport drum 12 and printing drum 24. In order to enable the transfer of the master sheet to the printing drum, the printing drum is provided with a leading gripping lever 124 that is pivotally mounted on a shaft 126. The gripping lever 124 has fingers 128 that can grip the leading edge of the master sheet. Immediately prior to the leading edge of the master sheet on the transport drum reaching the nip of two drums, the printing drum 24 is maintained stationary with the gripping lever 124 near the nip, and opened so that the fingers 128 can receive the leading edge of the master sheet.

As shown in FIG. 4, the leading edge L of the master sheet moves between the fingers 128 of the gripping lever 124 and the printing drum 24. The gripping lever 124 is then pivoted to a closed position to hold the leading edge of the master sheet firmly in place. At the same time, the printing drum 24 begins rotating, at the same surface speed as the transport drum 12. As the two drums thus rotate, the master sheet is stripped off the preliminary copy on the transport drum, and is wrapped around the printing drum. This continues until the entire master sheet has been wrapped about the printing drum 24. In order to hold the trailing edge of the master sheet firmly in place on the printing drum, a trailing gripping lever 130 is provided on the printing drum. The trailing gripping lever 130 has fingers 132 which can grip the trailing edge of the master sheet to hold it firmly in place. Initially, the trailing edge of the master sheet lies on top of the fingers 132. However, the lever 130 can be rapidly pivoted to a wide open position so that the trailing edge passes under it, and the lever 130 can then be closed tightly to hold the trailing edge in place. The master operated by a different arrangement shown in FIGS. 6

and 7.

As shown in FIG. 6, the gripping lever 94 on the transport drum is operated by a cam which can remain stationary in either of two positions or can rotate with the transport drum. A follower 143 mounted on the transport drum maintains a radially inward position when it rides on the lower portion 141 of the cam, to let a spring 144 keep the gripping lever fingers 98 closed against a sheet. However, when the follower rides on the upper cam portion 142, it forces the gripping lever to open.

At the beginning of the copying process, when the drum is in position to receive the zinc oxide preliminary copy sheet, the cam is in the position 140' shown in phantom lines, so that the gripping lever 94 is held open (the gripping lever 94 is then located in the position shown in FIG. 3, buy is open). When the transport drum begins to rotate, the cam 140 remains stationary for a moment to allow the fingers 98 to close and grip the sheet. The cam 140 then rotates with the transport drum to keep the gripping fingers closed. The cam 140 continues to rotate with the drum for a revolution, while the preliminary copy is made, its image is transferred to the master sheet, and the master sheet is wrapped onto the printing drum and oiled and inked. The cam is then stopped at the position 140 shown in solid lines, so that when the cam follower 143 of the gripping lever next reaches the position 145, it opens to release the preliminary copy remnant and allow it to move to the remnant basket. The transport drum continues to rotate while the cam 140 remains stationary. When the gripping lever 94 reaches the position 146 it again closes to grip a sheet of bond paper and when it reaches position it opens to allow the paper, which has been printed upon, to be delivered onto the output belt for delivery to the copies basket.

Control of rotation of the cam 140 is accomplished by a clutch 147 shown in FIG. 7, which is electrically operated by currentreceived through a slip ring (not shown). When the clutch is energized it couples the transport drum 12 to the cam 140 to rotate them together. When the clutch is deenergized, a solenoid 148 retains the cam 140 in one of the two stationary positions which it can assume. During rotation of the cam, the solenoid 148 is energized to withdraw its plunger and prevent interference with cam rotation. The solenoid 148 has a plunger that can be received in either of two recesses in a plate 149 that is fixed to the cam 140.

In making printed copies with the master sheet on the printing drum, sheets of paper are first picked up from the paper supply and fed along the conveyor 36 to the pick-up roll 30. As shown in FIG. 3, the pick-up roll 30 has a vacuum head 138 which can be turned on and off to pick up the release the leading edge of a sheet of bond paper. The pick-up roll 30 picks up a sheet of copy paper and carries its leading edge to the transport drum 12, which is positioned with the fingers 98 of the gripping lever open to receive the paper. The fingers 98 then clamp the paper on the transport drum while the pick-up roll releases it, and the drum then carries the paper to the printing drum 24. Sheets'of bond paper are applied to the transport drum 12 about l up-path from the nip between it and the printing drum, and the sheets are stripped off the transport drum about 60 downpath from the nip.

FIG. 5 is a simplified representation of a control system for operating the duplicating machine of the invention. An understanding of the control system can be gained by considering the steps through which the machine must progress in making copies. The control apparatus includes a preliminary material roller control 150 which starts and stops rotation of the feed roller 44 (see FIG. 2A) which feeds out zinc oxide preliminary copy material from the supply roll through the knife 48 to the transport drum 12. The control 150 is activated to start feeding out a sheet of zinc oxide material when a button 152 on the machine is pressed by the operator. After a preliminary feed counter 154 senses that the feed out roller 44 has turned enough to feed out a sheet of proper length, it delivers a signal to an off input of the roller control 150 to stop the feed rollers. The same signal is delivered from the counter 154 to a knife control 156 which operates the knife to cut off the sheet of zinc oxide paper from the rest of the roll. The other r01 lers 50, 52 which carry the sheet of zinc oxide paper to the transport drum rotate continuously.

When the leading edge of the zinc oxide material reaches the transport drum, apreliminary sheet detector 158 delivers a signal to the transport drum drive 162 which starts the rotation of the transport drum [2. After a few degrees of rotation of the transport drum, its-gripping lever closes over the leading edge of the zinc oxide sheet. The same signal from detector 158 which started transport drum rotation, passes through a delay circuit 159, which delivers a signal to a clutch energizing circuit 164. Thus, after a few additional degrees of transport drum rotation, the clutch 147 that couples the transport drum to the cam 140 is energized.

A transport drum multi-turn position sensor 166 controls many of the following operations of the machine, in accordance with the position of the transport drum. After the transport drum has carried the leading edge of the zinc oxide paper about one-quarter turn, the sensor 166 delivers a signal to an optical scanning control 168 to start the scanning of the document to be copied. The scanning control automatically turns off the scanning apparatus after the document has been completely scanned. At about the same time as optical scanning occurs, the transparent master material must be fed along its path to the transport drum. At the proper position of the transport drum, the sensor 166 delivers a signal to a master material feed roller control 170 to start rotation of the roller 68 (see FIG. 28) to start feeding out the master material. Another counter 172 senses when sufficient master material has been fed out, to stop the master fed roller drive 170 and to operate a master material knife control 174 that cuts off the master material. The sheet of master material is automatically fed onto the transport drum over the preliminary copy thereon.

Soon after the leading edge of the master material reaches the transport drum, a signal is delivered by the sensor 166 to an infrared station control 176 to turn on the infrared lamp and to move the transparent roller against the master sheet. After the transport drum has rotated sufliciently for all of the master sheet to have passed the infrared station, the sensor 166 delivers another signal to the infrared station control 176 to deactivate it.

Soon after the master material has passed the infrared station, it must be stripped off the preliminary copy and mounted on the printing drum. As mentioned above, the printing drum is initially stationary, with the leading edge gripper lever in an open position. As soon as the sensor 166 senses a transport drum position at which the leading edge of the mastermaterial should have just entered the space within the leading gripping lever .124 of the printing drum, a signal is delivered from the sensor 166 to a printing drum drive 178 to start rotation of the printing drum. The same signal is delivered to a leading gripping lever control 180 to cause the leading gripping lever 124 to close.

The printing drum continues to rotate until the sensor 166 senses a position of the transport drum wherein the trailing edge of the master sheet should have been received on the printing drum. A short time thereafter, the sensor 166 delivers a signal to a trailing gripping lever control 182 to cause a brief opening and closing of the trailing gripping lever. The same signal is delivered to a lithograph process control which starts the lithographic printing process. As mentioned earlier, this involves initial application of an oil and ink combination to the printing master, followed by steady application of ink to the printing master. Soon after the application of ink is begun, the clutch energizing circuit 164 is turned off to stop rotation of the cam that operates the gripping lever on the transport drum. Bond paper sheets are then repeatedly fed past the pick-up roll 30, onto the transport drum 12, and through the nip of the transport drum and printing drum to print on the paper. Control apparatus for feeding and carrying the sheets of paper are well known in the lithographic machine art, and therefore are not described in detail herein.

After the preliminary copy has been made and its toner transferred to the master sheet, it should be stripped from the transport drum. Referring again to FIG. 3, such stripping is accomplished by first pivoting the gripping lever 94 to release the leading edge of the preliminary copy, the portion of the lever beneath the fingers 98 actually lifting up the leading edge of the preliminary copy. When the preliminary copy reaches a guide 200, an edge of the edge of the guide leads the leading edge of the preliminary copy between a pair of belts of the remnant drive 26 to lead off the preliminary copy into the remnant basket. In order to later prevent sheets of bond paper being printed upon from entering the remnant basket, a copies guide 202 is provided which pivots into the position-shown in FIG. 3 at the beginning of the lithographic printing process, to lead the bond paper sheets onto the output conveyor 40.

After the required number of copies have been printed, the master sheet must be removed from the printing drum 24. First, the leading edge gripper lever 124 on the printing drum is lifted to release the leading edge of the master sheet. A guide 204 carries the master sheet from the printing drum, and causes it to move downwardly to the remnant drive, which carries it to the remnant basket. It may be noted that the fingers on each of gripping levers 94, 124 or 130 are spaced several inches apart along the width of the drums on which they are mounted, to leave spaces between the fingers. The leading edges of the guides 200 and 204 include sections positioned at these spaces, to prevent interference with the fingers while still permitting access to the surfaces of the transport and printing drums.

In some cases it is desirable to enable a printing master which was previously used and discarded in the remnant basket, or which has been made on another machine, to be utilized. This can be accomplished by feeding in the prepared master sheet through a conveyor belt 208 to the same path along which a sheet of master material is initially carried. However, the machine controls are set so that neither of the rollers which move out a sheet of zinc oxide material or transparent material is operated, and so that none of the stations about the transport drum 12 is activated. The prepared master sheet therefore moves from the conveyor 208 along the guides 112 to the transport drum l2, and from there it moves onto the printing drum 24 in the same manner as a sheet of master material, except that the infrared heating station 22 is not operated.

Although particular embodiments of the invention have been described and illustrated herein, it is recognized that modifications and variations may readily occur to those skilled in the art and, consequently, it is intended that the claims be interpreted to cover such modifications and equivalents.

What is claimed is:

l. Reproducing apparatus comprising:

a transport drum;

means for feeding a sheet of imagable material onto said drum;

means for forming on said sheet of imagable material the image of a document to be copied;

means for feeding a sheet of master material onto said transport drum over said imagable sheet bearing an image of said document;

means for transferring portions of said imagable sheet at the image area thereof to said master material while said sheet of imagable material is on said transport drum; printing drum means adjacent to said transport drum to form a nip between them, said printing drum means including means for receiving and wrapping about itself the sheet of master material from said transport drum;

means for depositing ink on the image portions of said sheet of master material on said printing drum means; and

means for feeding multiple copy material through the nip between said transport drum and saidprinting drum and into printing contact with said inked master material.

2. The apparatus described in claim 1 wherein:

against said sheet of master material over said transport drum, and a source of infrared radiation directed through said roller.

3. The apparatus described in claim 1 wherein:

said transport drum has a gripping lever pivotally mounted thereon for movement between closed and opened positions to grip and release the leading edge of sheets, a cam follower for operating said gripping lever between its closed and opened positions; and including a cam mounted adjacent to said cam follower for engaging it to operate said gripping lever; and

means for moving said can between first and second positions to change the angular position of said transport drum at which said gripping lever is operated, including means for selectively rotating and preventing the rotation of said cam with said transport drum to cease and begin, respectively, the operation of said gripping lever.

4. Reproducing apparatus comprising:

a transport drum having clamping means for clamping a sheet thereon;

means for feeding a sheet of electrophotographic material onto said drum, so it is held thereon by said clamping means;

means for imaging a document to be copied onto a sheet of said electrophotographic material on said drum;

means for developing the image on said sheet to form an electrophotographic copy; I

for feeding a sheet of transparent material onto said transport drum over said electrophotographic copy thereon;

means for applying infrared energy through said sheet of transparent material against said electrophotographic copy;

a printing drum mounted adjacent to said transport drum to form a nip between them, said printing drum including clamping means for engaging said sheet of transparent material from said transport drum, to peel it off said electrophotographic copy while said copy is held onto said transport drum;

means for feeding ink to a sheet of transparent material on said printing drum; and

means for feeding multiple copy material through the nip between said transport drum and said printing drum.

5. The apparatus described in claim 4 wherein:

said means for feeding a sheet of electrophotographic material and said means for feeding multiple copy material are spaced about said transport drum;

said clamping means on said transport drum includes a lever for holding down the leading edge of a sheet and a cam follower for operating said lever; and including a cam for moving said cam follower to operate said lever, and means for rotating said cam between first and second positions angularly spaced about the axis of rotation of said transport drum to operate said lever when it is adjacent to said means for feeding a sheet of electrophotographic material copy;

applying infrared radiation to said sheet of master material;

stripping off said sheet of master material from said preliminary copy and directly onto a printing drum which has a periphery adjacent to said transport drum so that is forms a nip between them, while at least part of said preliminary copy remains on said transport drum;

applying ink to portions of said sheet of master material on said printing drum; and

feeding sheets of paper through the nip between said drums to transfer ink to said sheets of paper. 

2. The apparatus described in claim 1 wherein: said master material is transparent to infrared radiation; and said means for transferring comprises an infrared-transparent roller, means for pressing said roller against said sheet of master material over said transport drum, and a source of infrared radiation directed through said roller.
 3. The apparatus described in claim 1 wherein: said transport drum has a gripping lever pivotally mounted thereon for movement between closed and opened positions to grip and release the leading edge of sheets, a cam follower for operating said gripping lever between its closed and opened positions; and including a cam mounted adjacent to said cam follower for engaging it to operate said gripping lever; and means for moving said can between first and second positions to change the angular position of said transport drum at which said gripping lever is operated, including means for selectively rotating and preventing the rotation of said cam with said transport drum to cease and begin, respectively, the operation of said gripping lever.
 4. Reproducing apparatus comprising: a transport drum having clamping means for clamping a sheet thereon; means for feeding a sheet of electrophotographic material onto said drum, so it is held thereon by said clamping means; means for imaging a document to be copied onto a sheet of said electrophotographic material on said drum; means for developing the image on said sheet to form aN electrophotographic copy; for feeding a sheet of transparent material onto said transport drum over said electrophotographic copy thereon; means for applying infrared energy through said sheet of transparent material against said electrophotographic copy; a printing drum mounted adjacent to said transport drum to form a nip between them, said printing drum including clamping means for engaging said sheet of transparent material from said transport drum, to peel it off said electrophotographic copy while said copy is held onto said transport drum; means for feeding ink to a sheet of transparent material on said printing drum; and means for feeding multiple copy material through the nip between said transport drum and said printing drum.
 5. The apparatus described in claim 4 wherein: said means for feeding a sheet of electrophotographic material and said means for feeding multiple copy material are spaced about said transport drum; said clamping means on said transport drum includes a lever for holding down the leading edge of a sheet and a cam follower for operating said lever; and including a cam for moving said cam follower to operate said lever, and means for rotating said cam between first and second positions angularly spaced about the axis of rotation of said transport drum to operate said lever when it is adjacent to said means for feeding a sheet of electrophotographic material and means for feeding multiple copy material, respectively.
 6. A method for making copies of a document comprising: wrapping a sheet of electrophotographic material about a transport drum; rotating said drum; imaging said document on portions of said sheet at a predetermined location about said drum while it rotates; applying toner to said sheet at a predetermined location about said drum while it rotates, to produce a preliminary copy; wrapping a sheet of transparent master material about said transport drum over said preliminary copy; applying infrared radiation to said sheet of master material; stripping off said sheet of master material from said preliminary copy and directly onto a printing drum which has a periphery adjacent to said transport drum so that is forms a nip between them, while at least part of said preliminary copy remains on said transport drum; applying ink to portions of said sheet of master material on said printing drum; and feeding sheets of paper through the nip between said drums to transfer ink to said sheets of paper. 